Remove debugger statement
fix(uiGridMenu): Only run applyHide when not shown

applyHide() was running on all GRID_SCROLL events, whether or not the menu
was visible. This was causing excess $digest() loops.
fix(Grid): Avoid too-early header height calc

renderContainers with no canvasWidth were having their heights calculated.
If their columns were wrapping around it would mean too large of a height
on that renderContainer, and thus would be propogated to ALL the other
containers (i.e. pinned containers).
WIP: render container wont capture keydown events if the cellnav wraps around to the other side and there are enough columns to cause some to not be rendered...